Jan 292015
 

One billion users on Facebook and more than 27,000 academic studies that cite it….at the start  of 2015 what do we really know about social media in our lives?  British Psychological Society summarised what science knows about Facebook and what it tells us about you.

A couple of quick warnings about unintended consequences…

A number of medications used by older people significantly increase the risk of dementia, according to the American Medical Association….The references are to US names for drugs.

And early menopause in women has been linked to environmental chemicals in their bodies. The substances also often affect ovarian function.

Now in good news – beer may be better for you than we thought. A substance in hops may help slow neurodegenerative diseases.

Walnuts might make you think better, too.

and a well known hormone has been found to increase sexual activity and desire to find a partner.

Have you ever walked into a room to get something and simply forgotten what it was? Just thinking about walking through a doorway can disrupt our memories.

 

Jan 292015
 

Into the LightWe’ve all had that experience of going purposefully from one room to another, only to get there and forget why we made the journey. Four years ago, researcher Gabriel Radvansky and his colleagues stripped this effect down, showing that the simple act of passing through a doorway induces forgetting. Now psychologists at Knox College, USA, have taken things further, demonstrating that merely imagining walking through a doorway is enough to trigger increased forgetfulness, according to the British Psychological Society Digest.

Zachary Lawrence and Daniel Peterson divided 51 students into two groups. One group spent a minute familiarising themselves with a large, furnished room. The other group wandered round the same room, but this one was divided in two by drapes, with a doorway connecting the two separated areas.

Next the participants were shown an abstract swirly image, and asked to remember it as they closed their eyes and imagined walking from the podium to the piano in the room they’d just experienced. For the second group only, this imagined walk meant passing through the room’s doorway (but the walk was the same distance as the other group’s). After imagining the walk in the room, both groups had to pick out the image they’d been shown earlier from an array of ten alternatives. The group who’d imagined passing through a doorway performed worse at the task than the first group who didn’t have to go through a doorway.

This result fits with the Event Horizon Model, which explains the forgetting effect of doorways in terms of the fact that we divide our memories into distinct events, that doorways trigger such a division, and that more forgetting occurs across event boundaries than within the same event. The new study shows that this event division effect can occur in our imagination and doesn’t require literally seeing a doorway and passing through it.

The first experiment wasn’t without issues – for example, the doorway group spent more time imagining their walk than the other group. Lawrence and Peterson conducted a second experiment in which two more groups of students were first exposed to a basic virtual reality room on a computer screen. One group saw a room with a partition and doorway; the other group saw the same room with no partition or doorway. Both groups were asked to imagine making a walk through the scene they’d been shown. This time both groups took the same time to complete their imagined journeys. But again, the group who imagined passing through a doorway performed worse when attempting to remember an abstract image they’d been shown before the imagined walk (roughly 18 per cent worse, which is comparable to the effect found for actually walking through a doorway).

“That walking through a doorway elicits forgetting is surprising because it is such a subtle perceptual feature compared to the rich environment in which it sits,” the researchers said, “that simply imagining such a walk yields a similar result is even more surprising, particularly when compared with actually walking through doorways.”

This effect of an imagined spatial boundary on forgetting is consistent with a related line of research that’s shown forgetting increases after temporal or other boundaries are described in narrative text. It seems real-world influences on your memory also apply in imagined realms, whether they’re of your own creation or someone else’s.

Source: British Psychological Society

Jan 292015
 

With over a billion users, Facebook is changing the social life of our species. Cultural commentators ponder the effects. Is it bringing us together or tearing us apart? Psychologists have responded too – Google Scholar lists more than 27,000 references with Facebook in the title. Common topics for study are links between Facebook use and personality, and whether the network alleviates or fosters loneliness. The torrent of new data is overwhelming and much of it appears contradictory. Here is the psychology of Facebook, digested:

Who uses Facebook?

Extraverts have more friends on FB
but shy people probably use it more


According to a survey of over a thousand people, “females, younger people, and those not currently in a committed relationship were the most active Facebook users“. Regarding personality, a study of over 1000 Australians reported that “[FB] users tend to be more extraverted and narcissistic, but less conscientious and socially lonely, than nonusers“. A study of the actual FB use of over a hundred students found that personality was a more important factor than gender and FB experience, with high scorers in neuroticism spending more time on FB. Meanwhile, extraverts were found to have more friends on the network than introverts (“the 10 per cent of our respondents scoring the highest in extraversion had, on average, 484 more friends than the 10 per cent scoring the lowest in extraversion”).

Other findings add to the picture, for example: greater shyness has also been linked with more FB use. Similarly, a study from 2013 found that anxiousness (as well as alcohol and marijuana use) predicted more emotional attachment to Facebook.

There’s also evidence that people use FB to connect with others with specialist interests, such as diabetes patients sharing information and experiences, and that people with autism particularly enjoy interacting via FB and other online networks.

Why do some people use Twitter and others Facebook?

High scorers in “need for cognition” prefer Twitter

Apparently most people use Facebook “to get instant communication and connection with their friends” (who knew?), but why use FB rather than Twitter? A 2014 paper suggested narcissism again is relevant, but that its influence depends on a person’s age: student narcissists prefer Twitter, while more mature narcissists prefer FB. Other research has uncovered intriguing links between personality and reasons for using FB. People who said they used FB as an informational tool (rather than socialising) tended to score higher on neuroticism, sociability, extraversion and openness, but lower on conscientiousness and “need for cognition”. The researchers speculated that using FB to seek and share information could be some people’s way to avoid more cognitively demanding sources such as journal articles and newspaper reports. The same study also found that higher scorers in sociability, neuroticism and extraversion preferred FB, while people who scored higher in “need for cognition” preferred Twitter.

What do we give away about ourselves on Facebook?

FB seems like the perfect way to present an idealised version of yourself to the world. However an analysis of the profiles of over 200 people in Germany and the US found that they reflected their actual personalities, not their ideal selves. Consistent with this, another study found that people who are rated as more likeable in the flesh also tend to be rated as more likeable based on their Facebook page. The things you choose to “like” on FB are also revealing. Remarkably, a study out last week found that your “likes” can be analysed by a computer programme to produce a more accurate profile of your personality than the profiles produced by your friends and relatives.

If our FB profiles expose our true selves, this raises obvious privacy issues. A study in 2013 warned that employers often trawl candidates’ FB pages, and that they view photos of drinking and partying as “red flags”, presumably seeing them as a sign of low conscientiousness (in fact the study found photos like these were linked with high extraversion, not with low conscientiousness).

Other researchers have looked specifically at how personality is related to the kind of content people post on FB. A 2014 study reported that “higher degrees of narcissism led to deeper self-disclosures and more self-promotional content within these messages. [And] Users with higher need to belong disclosed more intimate information“. Another study last year also reported that lonelier people disclose more private information, but fewer opinions.

You might also want to consider the friends you keep on FB – research suggests that their attractiveness (good-lookers give your rep a boost), and the statements they make about you on your wall, affect the way your own profile is perceived. Consider too how many friends you have – somewhat paradoxically, research finds that having an overabundance of friends leads to negative perceptions of your profile.

Finally, we heard about employers frowning on partying photos, but what else do you give away in your FB profile picture? It could reveal your cultural background according to a 2012 study that showed people from Taiwan were more likely to have a zoomed-out picture in which they were seen against a background context, while US users were more likely to have a close-up picture in which their face filled up more of the frame. Your FB pic might also say something about your current romantic relationship. When people feel more insecure about their partner’s feelings, they make their relationship more visible in their pics.

In case you’re wondering, yes, people who post more selfies probably are more narcissistic.

Is Facebook making us lonely and sad?

This is the crunch question that has probably attracted the most newspaper column inches (and books). A 2012 study took an experimental approach. One group were asked to post more updates than usual for one week – this led them to feel less lonely and more connected to their friends. Similarly, a survey of over a thousand FB users found links between use of the network and greater feelings of belonging and confidence in keeping up with friends, especially for people with low self-esteem. Another study from 2010 found that shy students who use FB feel closer to their friends (on FB) and have a greater sense of social support. A similar story is told by a 2013 paper that said feelings of FB connectedness were associated with “with lower depression and anxiety and greater satisfaction with life” and that Facebook “may act as a separate social medium ….  with a range of positive psychological outcomes.” This recent report also suggested the site can help revive old relationships.

Yet there’s also evidence for the negative influence of FB. A 2013 study texted people through the day, to see how they felt before and after using FB. “The more people used Facebook at one time point, the worse they felt the next time we text-messaged them; [and] the more they used Facebook over two-weeks, the more their life satisfaction levels declined over time,” the researchers said.

Other findings are more nuanced. This study from 2010 (not specifically focused on FB) found that using the internet to connect with existing friends was associated with less loneliness, but using it to connect with strangers (i.e. people only known online) was associated with more loneliness. This survey of adults with autism found that greater use of online social networking (including FB) was associated with having more close friendships, but only offline relationships were linked with feeling less lonely.

Facebook could also be fuelling envy. In 2012 researchers found that people who’d spent more time on FB felt that other people were happier, and that life was less fair. Similarly, a study of hundreds of undergrads found that more time on FB went hand in hand with more feelings of jealousy. And a paper from last year concluded that “people feel depressed after spending a great deal of time on Facebook because they feel badly when comparing themselves to others.” However, this new report (on general online social networking, not just FB) found that heavy users are not more stressed than average, but are more aware of other people’s stress.

Is Facebook harming students’ academic work?

This is another live issue among newspaper columnists and other social commentators. An analysis of the grades and FB use of nearly 4000 US students found that the more they used the network to socialise, the poorer their grades tended to be (of course, there could be a separate causal factor(s) underlying this association). But not all FB use is the same – the study found that using the site to collect and share information was actually associated with better grades. This survey of over 200 students also found that heavier users of FB tend to have lower academic grades, but note again that this doesn’t prove a causal link. Yet another study, this one from the University of Chicago, which included more convincing longitudinal data, found no evidence for a link between FB use and poorer grades; if anything there were signs of the opposite pattern. Still more positive evidence for FB came from a recent report that suggested FB – along with other social networking tools – could have cognitive benefits for elderly people.

And finally, some miscellaneous findings

That was our digest of the psychology of Facebook – please tell all your friends, on and off Facebook! Oh, and don’t forget to visit the Research Digest Facebook page.

Source:  The British Psychological Society
_____________

Jan 292015
 

photodune-1237621-beer-xsThe health-promoting perks of wine have attracted the spotlight recently, leaving beer in the shadows. But scientists are discovering new ways in which the latter could be a more healthful beverage than once thought. They’re now reporting in ACS’ Journal of Agricultural and Food Chemistry that a compound from hops could protect brain cells from damage — and potentially slow the development of disorders such as Alzheimer’s and Parkinson’s diseases.

Jianguo Fang and colleagues note that mounting evidence suggests that oxidative damage to neuronal cells contributes to the development of diseases that originate in the brain. If scientists could find a way to guard these cells from this type of damage, they might be able to help prevent or slow down Alzheimer’s disease, Parkinson’s disease and other neurodegenerative conditions. One compound found in hops, called xanthohumol, has gotten the attention of researchers for its potential benefits, including antioxidation, cardiovascular protection and anticancer properties.

Fang’s team decided to test xanthohumol’s effects on brain cells.

In lab tests, the researchers found that the compound could protect neuronal cells and potentially help slow the development of brain disorders. The scientists conclude xanthohumol could be a good candidate for fighting such conditions.

Source: AMERICAN CHEMICAL SOCIETY

Jan 292015
 

ChemicalsWomen whose bodies have high levels of chemicals found in plastics, personal-care products, common household items and the environment experience menopause two to four years earlier than women with lower levels of these chemicals, according to a new study at Washington University School of Medicine in St. Louis.

The findings are reported online Jan. 28 in the journal PLOS ONE.

The researchers looked at levels in blood and urine of 111 chemicals that are suspected of interfering with the natural production and distribution of hormones in the body. While several smaller studies have examined the link between so-called endocrine-disrupting chemicals and menopause, the new research is the first to broadly explore the association between menopause and individual chemicals on a large scale, using a nationally representative sample of patients across the United States.

“Chemicals linked to earlier menopause may lead to an early decline in ovarian function, and our results suggest we as a society should be concerned,” said senior author Amber Cooper, MD, an assistant professor of obstetrics and gynecology.

A decline in ovarian function not only can adversely affect fertility but also can lead to earlier development of heart disease, osteoporosis and other health problems. Other problems already linked to the chemicals include certain cancers, metabolic syndrome and, in younger females, early puberty.

“Many of these chemical exposures are beyond our control because they are in the soil, water and air,” Cooper said. “But we can educate ourselves about our day-to-day chemical exposures and become more aware of the plastics and other household products we use.”

For example, Cooper recommends that people microwave food in glass or paper containers instead of in plastic and try to learn more about the ingredients in cosmetics, personal-care products and food packaging they use every day.

Although many of the chemicals included in the study have been banned from U.S. production because of their negative health effects, they still are produced globally and are pervasive in the environment.

In the study, Cooper and researchers at the University of Missouri-Kansas City School of Medicine and the Wadsworth Center at the State University of New York at Albany analyzed data collected from 1999-2008 as part of the National Health and Nutrition Examination Survey, conducted by the U.S. Centers for Disease Control and Prevention.

The survey included data from 31,575 people, including 1,442 menopausal women who had been tested for levels of endocrine-disrupting chemicals. The average age of these women was 61, and none was using estrogen-replacement therapies or had had surgery to remove ovaries.

The survey was designed so that the women who had undergone chemical testing would represent a population of almost 9 million menopausal women.

The women’s blood and urine samples were analyzed for exposures to 111 mostly man-made chemicals, which included known reproductive toxins and/or those that take more than a year to break down. Chemicals from the following categories were analyzed in the survey: dioxins/furans (industrial combustion byproducts); phthalates (found in plastics, common household items, pharmaceuticals and personal-care products including lotions, perfumes, makeup, nail polish, liquid soap and hair spray); phytoestrogens (plant-derived estrogens); polychlorinated biphenyls (PCBs, coolants); phenolic derivatives (phenols, industrial pollutants); organophosphate pesticides; surfactants; and polycyclic aromatic hydrocarbons (combustion products).

The researchers identified 15 chemicals — nine PCBs, three pesticides, two phthalates and a furan (a toxic chemical) — that warrant closer evaluation because they were significantly associated with earlier ages of menopause and potentially have detrimental effects on ovarian function.

“Earlier menopause can alter the quality of a woman’s life and has profound implications for fertility, health and our society,” Cooper said. “Understanding how the environment affects health is complex. This study doesn’t prove causation, but the associations raise a red flag and support the need for future research.”

Source: WASHINGTON UNIVERSITY SCHOOL OF MEDICINE

 

Jan 292015
 

Young girl on bathroom scale looking upsetTeens who mistakenly perceive themselves as overweight are actually at greater risk of obesity as adults, according to research findings forthcoming in Psychological Science, a journal of the Association for Psychological Science.

“Our research shows that psychological factors are important in the development of obesity,” says psychological scientist and study author Angelina Sutin of Florida State University College of Medicine. “The American Academy of Pediatrics recommends addressing body image with adolescents at every well child visit. Misperception is typically taken as a sign of an eating disorder, such as anorexia or bulimia, but our research shows that it may also signal a long-term risk of obesity.”

This is a photo of feet on a scale.In previous work, Sutin and study co-author Antonio Terracciano had found that weight-based discrimination was associated with increased risk of obesity. They wondered whether individuals’ own perceptions — self-stigmatization — might be just as harmful, especially during such a critical developmental period as adolescence.

The researchers used the National Longitudinal Study of Adolescent Health, known as Add Health, to examine height, weight, and self-perception data from a total of 6523 adolescents who participated in the study when they were about 16 years old and again when they were about 28.

At age 16, the participants were asked to rate how they thought of themselves in terms of weight, with response options ranging from very underweight (a score of 1) to very overweight (a score of 5). The researchers were specifically interested in looking at the outcomes for teens who saw themselves as overweight, even though they were a healthy weight by medical standards.

Compared to teens who perceived their weight accurately, adolescents who misperceived themselves as overweight had a 40% greater risk of becoming obese as adults, defined as having a body mass index of 30 or more. This misperception was also associated with the overall amount of weight the adolescents gained.

But why would seeing themselves as heavier than they actually are predispose teens to later weight gain?

There are probably several mechanisms at work, say Sutin and Terracciano. These teens may be more likely to engage in unhealthy weight-control behaviors, like using diet pills or vomiting, that are known to be associated with long-term weight gain. The psychological factors that lead them to misperceive their weight might also be linked with lower self-regulatory abilities. And the teens are likely also influenced by weight-related stigmatization, which is itself associated with obesity.

Ultimately, these factors may result in a self-fulfilling prophecy:

“Adolescents who misperceive themselves as being overweight may not take the steps necessary to maintain a healthy weight, because as they gain weight, they physically become what they have long perceived themselves to be,” the researchers explain.

Sutin and Terracciano were surprised to find that the link between perceptions and later obesity was especially strong for boys: Boys who misperceived themselves as overweight showed an 89% increased risk of later obesity compared to those who perceived themselves accurately.

“At this point, it is not really clear why the association is stronger for boys,” says Sutin. “It may be that girls are more attentive to their weight and may intervene earlier when they experience any weight gain. As such, the self-fulfilling prophesy may be stronger for boys than for girls. Physicians and other health care providers may also notice weight gain sooner for girls than for boys, or may be more likely to address any weight gain with girls than with boys. We were unable, however, to test exactly why there is this difference across the sexes.”

While the focus for intervention is often put on girls and teens who are already overweight, these findings show that many more adolescents may be at risk for later health issues. As such, the findings have broad implications, not just for teens and their parents, but also for medical practitioners and even policymakers.

“This research underscores the importance of the AAP’s recommendation,” says Sutin. “It is clear that the determinants of obesity are complex and range from genetics to the social environment and public policy. We need a greater understanding of determinants at all levels, including the psychological determinants, to effectively address our current challenges with the prevalence of obesity.”

Source: Association for Psychological Science.

 

Jan 292015
 

85793_webPsychopathic violent offenders have abnormalities in the parts of the brain related to learning from punishment, according to an MRI study led by Sheilagh Hodgins and Nigel Blackwood. “One in five violent offenders is a psychopath. They have higher rates of recidivism and don’t benefit from rehabilitation programmes. Our research reveals why this is and can hopefully improve childhood interventions to prevent violence and behavioural therapies to reduce recidivism,” explained Professor Hodgins of the University of Montreal and Institut universitaire en santé mentale de Montréal.

“Psychopathic offenders are different from regular criminals in many ways. Regular criminals are hyper-responsive to threat, quick-tempered and aggressive, while psychopaths have a very low response to threats, are cold, and their aggressively is premeditated,” added Dr. Nigel Blackwood, who is affiliated with King’s College London. “Evidence is now accumulating to show that both types of offenders present abnormal, but distinctive, brain development from a young age.”

In order to develop programs that prevent offending and rehabilitation programs that reduce re-offending, it is essential to identify the neural mechanisms underlying psychopath’s persistent violent behaviour. “We have been using Magnetic Resonance Imaging to study brain structure and function in a sample of violent offenders in England, one group with psychopathy and one without, and a sample of healthy non-offenders. We have found structural abnormalities in both gray matter and specific white matter fiber tracts among the violent offenders with psychopathy,” Hodgins explained. Grey matter is mostly involved with processing information and cognition, while white matter coordinates the flow of information between different parts of the brain.

12 violent offenders with antisocial personality disorder and psychopathy, 20 violent offenders with antisocial personality disorder but not psychopathy, and 18 healthy non-offenders participated in the study. The offenders had been convicted of murder, rape, attempted murder and grevious bodily harm, and were recruited from Britain’s probation service. “We observed reductions in gray matter volumes bilaterally in the anterior rostral prefrontal cortex and temporal poles relative to the other offenders and to the non-offenders,” Hodgins said. These brain regions are involved in empathy, the processing of pro-social emotions such as guilt and embarrassment, and moral reasoning. “Abnormalities were also found in white matter fiber tracts in the dorsal cingulum, linking the posterior cingulate cortex to the medial prefrontal cortex that were specifically associated with the lack of empathy that is typical of psychopathy,” Blackwood added. These same regions are involved in learning from rewards and punishment.

In order to engage in appropriate behaviour, it is essential to learn from punishment, both real and imagined. “Most individuals do not walk in front of buses as they can imagine the horrible consequences if the bus hits them. Offenders do not walk in front of buses either, suggesting that they also learn from punishment, nor do they show less sensitivity to punishment than others,” Hodgins said. “In childhood, both psychopathic and non-psychopathic offenders alike are repeatedly punished by parents and teachers for breaking rules and for assaulting others, and from adolescence onwards, they are frequently incarcerated. Yet they persist in engaging in violent behaviour towards others. Thus, punishment does not appear to modify their behaviour.”

While inside the brain scanner, the violent offenders and non-offenders completed a task that assessed their ability to adjust their behaviour when the consequences of their responses changed from positive to negative. The task was an image matching game – sometimes points were awarded for correctly pairing images, sometimes they weren’t. “When these violent offenders completed neuropsychological tasks, they failed to learn from punishment cues, to change their behaviour in the face of changing contingencies, and made poorer quality decisions despite longer periods of deliberation,” Blackwood explained.

The researchers also examined activity across the brain during the completion of the task. “We found that the violent offenders with psychopathy, as compared to both the violent offenders without psychopathy and the non-offenders, displayed abnormal responding to punishment within the posterior cingulate and insula when a previously rewarded response was punished. Our previous research had shown abnormalities in the white matter tract connecting these two regions. In contrast, the violent offenders without psychopathy showed brain functioning similar to that of the non-offenders,” Blackwood explained. “These results suggest the violent offenders with psychopathy are characterized by a distinctive organization of the brain network that is used to learn from punishment and from rewards.”

Deciding on what to do involves generating a list of possible actions, weighing the negative and positive consequences of each, and hopefully choosing the behaviour most likely to lead to a positive outcome. “Offenders with psychopathy may only consider the possible positive consequences and fail to take account of the likely negative consequences. Consequently, their behavior often leads to punishment rather than reward as they had expected,” Hodgins said. “Punishment signals the necessity to change behaviour. Clearly, in certain situations, offenders have difficulty learning from punishment to change their behaviour.”

Conduct problems and the antecedents of psychopathy emerge early in life when learning-based interventions have the potential to alter brain structure and functioning. “Programs that teach parents optimal parenting skills lead to significant reductions in conduct problems among their children, except among those who are callous and insensitive to others. As our studies and those of others show, the abnormalities of brain structure and function associated with persistent violent behavior are subtle and complex,” Blackwood explained. “The results of our studies are providing insights into the neural mechanisms characterizing adult violent offenders that may be used, along with other findings, in designing programs to reduce recidivism. Our results also provide hypotheses about the abnormal development of violent offenders to be tested in studies of children.”

This information is critical to the development of programs to prevent violent criminality. “Since most violent crimes are committed by men who display conduct problems from a young age, learning-based interventions that target the specific brain mechanisms underlying this behaviour pattern and thereby change the behaviour would significantly reduce violent crime,” Hodgins said.

Source: UNIVERSITY OF MONTREAL

 

Jan 282015
 

Approximately 170,000 people die from alcoholic cirrhosis of the liver in Europe every year. Although alcohol is the most important risk factor, less is known about the significance of different patterns of drinking.

Currently scientists believe that cirrhosis is a function of the volume of alcohol consumed irrespective of patterns of drinking. Investigators have now established that alcohol drinking pattern has a significant influence on the risk of cirrhosis and that daily drinking increases that risk compared with drinking less frequently. Results are published in the Journal of Hepatology.

“For the first time, our study points to a risk difference between drinking daily and drinking five or six days a week in the general male population, since earlier studies were conducted on alcohol misusers and patients referred for liver disease and compared daily drinking to ‘binge pattern’ or ‘episodic’ drinking,” observed lead investigator Gro Askgaard, MD, of the Department of Hepatology, Copenhagen University Hospital, Rigshospitalet, and the National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark. “Since the details of alcohol induced liver injury are unknown, we can only speculate that the reason may be that daily alcohol exposure worsens liver damage or inhibits liver regeneration.”

To examine the patterns of drinking associated with alcoholic cirrhosis, researchers in Denmark investigated the risk of alcoholic cirrhosis among nearly 56,000 participants aged between 50 and 64 in the Danish Cancer, Diet, and Health study (1993-2011). All participants first completed a detailed food-frequency questionnaire along with a questionnaire regarding lifestyle and background factors (alcohol, smoking, physical activity, and years of education) as well as a brief physical examination including measurement of waist circumference. Amount of alcohol intake was reported as the average amount per week of specific types of alcohol: beer, wine, and liquor. Participants were also asked to report their average amount of alcohol intake when they were 20-29, 30-39, 40-49, and 50-59 years old. Follow-up information came from national registers.

The researchers calculated hazard ratios (HRs) for alcoholic cirrhosis in relation to drinking frequency, lifetime alcohol amount, and beverage type.

Among the 55,917 participants, 257 men and 85 women developed alcoholic cirrhosis, corresponding to an incidence rate of 66 in men and 19 in women per 100,000 person-years. There were no cases of alcoholic cirrhosis among lifetime abstainers.

In men, the results showed that daily drinking increases the risk of alcoholic cirrhosis compared with drinking less frequently. The results also suggest that recent alcohol consumption, and not lifetime alcohol consumption, is the strongest predictor of alcoholic cirrhosis.

Compared with beer and liquor, wine seems to be associated with a lower risk of alcoholic cirrhosis up to a moderate level of weekly alcohol amount. Among women, researchers were unable to draw firm conclusions due to low statistical power, though in general they found the same trends.

“Earlier studies regarding lifetime alcohol consumption and risk of alcoholic cirrhosis reached opposite conclusions, for instance, whether a previous high level of alcohol amount predicted future risk, even after having cut down,” commented Dr. Askgaard. “From a clinical point of view, this is relevant in order to execute evidence-based counselling, and from a public health perspective, it may guide health interventions for the general population.”

“This is a timely contribution about one of the most important, if not the most important risk factor for liver cirrhosis globally, because our overall knowledge about drinking patterns and liver cirrhosis is sparse and in part contradictory,” said noted expert Jürgen Rehm, PhD, Director of the Social and Epidemiological Research Department of the Centre for Addiction and Mental Health, Toronto. “The work of Askgaard and colleagues not only increases our knowledge, but also raises questions for future research. The question of binge drinking patterns and mortality is far from solved, and there may be genetic differences or other covariates not yet discovered, which play a role and could explain the different empirical findings.”

Source: ELSEVIER HEALTH SCIENCES

Jan 282015
 

CREDIT Image courtesy of Zuker Lab, HHMI at Columbia University

CREDIT
Image courtesy of Zuker Lab, HHMI at Columbia University

The thirst-regulating circuit is located in a region of the brain called the subfornical organ (SFO). “We view the SFO as a dedicated circuit that has two elements that likely interact with each other to maintain the perfect balance, so you drink when you have to and you don’t drink when you don’t need to,” says Charles Zuker, an HHMI investigator at Columbia University who led the research. By doing so, the circuit ensures animals take in the right amount of fluid to maintain blood pressure, electrolyte balance, and cell volume. This work, led by postdoctoral fellow Yuki Oka was published January 26, 2015, in the journal Nature.

Zuker’s lab is primarily interested in the biology of taste. Their studies have identified the receptors for the five basic tastes (sweet, sour, bitter, uammi and salt), and shown that the nervous system devotes multiple pathways to sensing and responding to salt. These circuits ensure that salt is appealing to humans at low concentrations, but not at high concentrations. “This is how the taste system regulates salt intake, which is very important for salt homeostasis in the body,” says Oka. “But this is just one side of the coin. Salt intake has to be balanced by water intake.”

The scientists knew a different mechanism must be responsible for controlling an animal’s water intake. “There are no concentration changes for water — water is water,” Oka says. “But when you’re thirsty, water is really attractive.” Zuker and Oka set out to determine how the brain regulated the motivation to drink.

They began their search in the brain region known as the SFO, which shows increased activity in dehydrated animals. The SFO is one of the few regions of the brain located outside the blood-brain barrier, meaning it has direct contact with body fluids. “These cells might then have the opportunity to directly sense electrolyte balance in body fluids,” Zuker points out.

Past experiments in which researchers had elecrically stimulated various circumventricular organs in the brain of mice, including the SFO, had yielded inconsistent results. Oka wanted to find out if their were specific cells in the SFO that triggered drinking behavior. By analyzing genetic markers, he identified three distinct cell types in the SFO: one set of excitatory cells, one set of inhibitory cells, and a third population of supporting cells known as astrocytes.

“If these neurons really mediated key aspects in driving the motivation to drink, then their activation should trigger active drinking, irrespective of the degree of fluid satiety,” Zuker says. “And if you silence these populations, you should suppress the motivation to drink, even if you are extraordinarily thirsty.”

To test these predictions, Oka introduced a light-sensitive protein into cells in the SFO, enabling the scientists to selectively activate those cells in the mice. Using blue light from a laser, they then switched on the excitatory cells in the SFO of mice that had already had plenty to drink. The results were dramatic.

“There is an animal that is happily wondering around, with zero interest in drinking. You activate this group of excitatory neurons, and it just beelines to the water spout,” Zuker says. “As long as the light is on, that mouse keeps on drinking.” The animals were uninterested in other fluids, but would avidly drink water for prolonged periods, consuming as much eight percent of their body weight. For humans, that would amount to about 1.5 gallons of water, Oka points out.

“It’s very exciting,” Zuker says. “This circuit informs and directs the mouse into a complex program of actions and behaviors: “I’m thirsty. I need to identify a source of water. I have to go where the water is. I have to begin to consume that water and I have to continue until this signal is suppressed.”

The next step was testing the effect of the inhibitory neurons in the SFO. When Oka switched those cells on in thirsty animals, the mice reduced their water intake by about 80 percent. Activating the inhibitory cells did not affect the animals’ interest in food or salt, indicating that the neurons specifically regulate water consumption.

The two groups of cells appear to work together to respond to changing hydration levels and maintain fluid balance, the scientists say. “You can imagine this must be a very tightly controlled feedback loop,” Zuker says. “As fluid is being consumed, the electrolyte balance is changing, and this is being sensed.”

Zuker also points out “the behavior of the mouse is independent of learning, experience, or context,” indicating that the thirst-regulating circuit is hard-wired into the brain. Mingyu Ye, another postdoctoral fellow in Zuker’s lab also participated in the study. Yuki Oka recently acccepted a position as assistant professor at the California Institute of Technology.

Source: Howard Hughes Medical Institute

Jan 282015
 

woman looking picturesWomen rate emotional images as more emotionally stimulating than men do and are more likely to remember them. However, there are no gender-related differences in emotional appraisal as far as neutral images are concerned. These were the findings of a large-scale study by a research team at the University of Basel that focused on determining the gender-dependent relationship between emotions, memory performance and brain activity. The results will be published in the latest issue of the Journal of Neuroscience.

It is known that women often consider emotional events to be more emotionally stimulating than men do. Earlier studies have shown that emotions influence our memory: the more emotional a situation is, the more likely we are to remember it. This raises the question as to whether women often outperform men in memory tests because of the way they process emotions. A research team from the University of Basel’s “Molecular and Cognitive Neurosciences” Transfaculty Research Platform attempted to find out.

With the help of 3,398 test subjects from four sub-trials, the researchers were able to demonstrate that females rated emotional image content – especially negative content – as more emotionally stimulating than their male counterparts did. In the case of neutral images, however, there were no gender-related differences in emotional appraisal. In a subsequent memory test, female participants could freely recall significantly more images than the male participants. Surprisingly though, women had a particular advantage over men when recalling positive images. “This would suggest that gender-dependent differences in emotional processing and memory are due to different mechanisms,” says study leader Dr Annette Milnik.

Increased brain activity

Using fMRI data from 696 test subjects, the researchers were also able to show that stronger appraisal of negative emotional image content by the female participants is linked to increased brain activity in motoric regions. “This result would support the common belief that women are more emotionally expressive than men,” explained Dr Klara Spalek, lead author of the study.

The findings also help to provide a better understanding of gender-specific differences in information processing. This knowledge is important, because many neuropsychiatric illnesses also exhibit gender-related differences. The study is part of a research project led by professors Dominique de Quervain and Andreas Papassotiropoulos at the University of Basel, which aims to increase the understanding of neuronal and molecular mechanisms of human memory and thereby facilitate the development of new treatments.

Source: University of Basel

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